In the field of tufting, it is well known that more than one needle bar may be required in order to accomplish a particular pattern of color and/or texture on the top side of the carpet. In order to accomplish this, the needle bars are spaced apart one from the other in the direction of travel of the backing material. By so spacing the needle bars, each may move independently of the other in a transverse direction with respect to the backing material. In order to prevent the individual needles from colliding with the corresponding hooks provided for catching and/or cutting the yarn pressed through the backing material, the needle bars are staggered at specific increments such that the needles are staggered. For example, the individual needles carried by each needle bar are spaced two units apart. The needle bars are staggered in a transverse direction by one unit. Thus, looking at the needle carried by both needle bars in the direction of travel of the backing material, the needles are spaced apart a distance of one unit.
Due to the distance between the needle bars, distinct patterns are difficult to attain. The forward needle bar has completed its portion of the pattern for at least one row of tuft before the rearward needle bar is able to complete the pattern on that row. In effect, it is well known that this stagger creates a transition between patterns. This stagger is most obvious in patterns wherein squares, such as in a checkerboard pattern, are attempted. At least two of the corners are typically truncated. This is also noticeable in the transition from a high pile to a low pile texture. It is well known that this transition typically produces a smooth curve effect as opposed to a distinct change in pile height between two consecutive loops.
Other tufting machines have been produced to allow for increased performance capabilities in the manufacture of patterned carpet. Typical of the art are those devices disclosed in the following U.S. Patents:
______________________________________ U.S. Pat. No. Inventor(s) Issue Date ______________________________________ 2,842,080 F. W. E. Hoeselbarth Jul 8, 1958 2,850,994 A. H. Crawford Sep 9. 1958 3,019,748 J. L. Card Feb 6, 1962 3,095,840 W. H. Ballard Jul 2, 1963 3,095,841 W. H. Ballard, et al. Jul 2, 1963 3,138,126 R. T. Card Jun 23, 1964 3,162,155 A. E. Charles Dec 22, 1964 3,396,687 H. F. Nowicki Aug 13, 1968 3,633,523 R. T. Card Jan 11, 1972 3,850,120 O. R. Jackson Nov 26, 1974 4,226,196 D. Booth Oct 7, 1980 4,398,479 P. A. Czelusniak, Jr. Aug 16, 1983 4,800,828 C. W. Watkins Jan 31, 1989 5,058,518 R. T. Card, et al. Oct 22, 1991 5,193,472 P. H. Crossley Mar 16, 1993 ______________________________________
Of these devices, those disclosed by Hoeselbarth ('080), Crawford ('994), Ballard ('840), Ballard, et al. ('841), Card ('126), and Charles ('155) are directed toward devices designed to allow variation of the pile height to create a contoured carpet. The Card ('126) device is specifically designed to fabricate cut pile carpet having high- and low-cut pile. None of these references teaches the use of a plurality of independently-operable needle bars for creating a selected pattern.
The remainder of the prior art references disclose various devices, each incorporating a pair of needle bars which may be moved with respect to one another. Typically, as illustrated by Card ('748), Nowicki ('687), Card ('523), Jackson ('120), Booth ('196), Watkins ('828), Card, et al. ('518), and Crossley ('472), the individual needle bars are spaced apart in the direction of travel of the backing material. The needle bars may thus be moved transversely to approximate a selected pattern. Nowicki best illustrates the typical patterns achievable by these types of devices. FIGS. 16-18 therein illustrate the "footprints" of the two needle bars as they move independently of each other. FIG. 16 illustrates the movement of the two needle bars in opposite directions at all times. FIG. 17 illustrates movement of both in opposite directions for two steps and in the same direction for two steps. FIG. 18 illustrates one needle bar moving left and right with the second needle bar remaining in one position.
FIGS. 8-11 of the Nowicki disclose the use of varying the pile height to hide particular filaments in a selected portion of the pattern. Typically, the variation of the pile height is accomplished through the selection of the looper member, or hook, associated with a particular needle. Alternatively, this may be accomplished by using a pattern wheel which controls the depth of penetration of the individual needles into the backing material.
The device taught by Czelusniak, Jr. ('479) includes a pair of needle bars which are indexed such that the two rows of needles carried by the individual needle bars are aligned to form a single row of needles. The two individual needle bars are held in abutment in the lower portion of the needle stroke using a tension spring member. At the top of the stroke, a lever is engaged to separate the two needle bars one from the other. A pattern means then shifts the needle bars as required to accomplish the selected design. The two needle bars attached at their respective ends in essentially a loop configuration such that as one is moved in one direction, the other is moved in the opposite direction an equal distance. Czelusniak does not disclose a device for varying the pile height for selected tufts. Nor does Czelusniak disclose a device for tufting fabrics using two needle bars collectively as either of an in-line needle bar or a pair of staggered needle bars. The Czelusniak device may only be used in an in-line needle bar application as the needle bars remain biased one toward the other. When in the in-line position, the Czelusniak disclosure fails to provide a means whereby the spacing between the individual needles is accurately maintained. The needles 44 are received between boss portions 43b, to each of which is mounted a needle 45. Needles 44 and needles 45 are of different lengths due to this configuration, and needles 44 are at a high risk of breakage if the needle bars 42 and 43 are moved toward one another such that the needles 44 engage the terminal portion of the boss portions 43b.
None of the prior art devices show the use of a dual needle bar arrangement as both a standard two needle bar configuration and an in-line configuration. Further, none of the prior art references discloses the use of a dual needle bar arrangement in an in-line fashion wherein the movement of each needle is independent of the movement of the other.
Therefore, it is an object of this invention to provide a means for tufting a selected fabric wherein at least two needle bars are used, the needle bars being provided with registered faces for receiving one another such that the needles carried by both needle bars are positioned to define a single row of needles.
Further, it is an object of the present invention to provide a means for moving each needle bar in a transverse direction of the travel of the selected fabric, each needle bar being moved independently of the other.
Another object of the present invention is to provide at least one means for controlling the rate of feed of a plurality of filaments to be tufted into the selected fabric.
Still another object of the present invention is to provide a means for independently controlling the feed rate of a plurality of groups of filaments to be tufted.
Yet another object of the present invention is to provide a means whereby the needles carried by each needle bar in the plural needle bar configuration are each substantially similar one to another.
Still another object of the present invention is to provide a means for protecting the needles carried by each needle bar when the needle bars are being positioned to define an in-line needle bar.